1. Field of the Invention
This invention relates to a gas log apparatus and, more particularly, to a heat producing gas log apparatus which circulates air through heat exchanger tubes disposed above a gas burner for heating the air and exhausting the heated air into the environment.
2. Description of the Prior Art
It is known in the art to circulate cool ambient air from the environment through ducting disposed adjacent to an open flame and exhaust the air which is heated thereby back into the environment For example, U.S. Pat. No. 4,408,594 to Shimek, et al., discloses a hollow heated grate for a fireplace in which a blower circulates air through a plenum comprising a plurality of hollow tubes and exhausts the heated air back into the environment.
Air circulating systems have also been employed in gas log burners. U.S. Pat. No. 5,000,162 to Shimek, et al., discloses a heating system for a gas log apparatus wherein air enters at one side of the system, passes through ductwork formed under the gas flame and into the ambient environment at the other side of the system. As with U.S. Pat. No. 4,408,594, the air circulates through the ductwork disposed underneath the gas flame with a resultant relatively poor heat transfer rate therebetween.
It is also known in the art to heat air flowing through a conduit which is disposed above a gas flame. U.S. Pat. No. 4,291,670 to Hyatt and Canadian Patent No. 1,239,314 to Martin both disclose a heat exchanger having a plurality of formed hollow cylindrical tubes disposed above an open flame source. Air enters the plurality of tubes near the bottom of the apparatus and is circulated through the plurality of tubes above the open flame source. The air flowing through the tubes is heated by the open flame source and is exhausted from the outlet of the tubes near the top of the apparatus. The Hyatt and Martin heat exchangers were a step forward in the art but have a relatively high dimensional profile.
What is needed is a heat exchanger integrated with a gas log apparatus which has a relatively low dimensional profile, and which further has an output temperature from the heat exchanger which is higher than heretofore possible with the prior art.